An anesthetic filling system is used to cooperate with an evaporator and comprises a container containing an anesthetic and a connecting valve structure with one end fixed at a drug outlet of the container, wherein another end of the connecting valve structure is inserted into a filling port of the evaporator. Generally, in order to ensure the sealing of the connection, an O-shaped ring is sheathed on an end part of the connecting valve structure, and an outer side wall of the connecting valve structure and an inner side wall of the filling port press the O-shaped ring. Due to the work requirement, multiple times of insertion and pulling of connecting valve structure into and out of the filling port of the evaporator are conducted, which further results in abrasion of the O-shaped ring and formation of impurities, besides, such O-shaped ring is generally made from (ethylene propylene diene monomer) EPDM material, during the friction of the insertion and pulling of the O-shaped ring into and out of the filling port, BHT exudate will occur, the BHT exudate will remain in the evaporator and be prone to be oxidized and yellowed in a high temperature state, which may result in trouble to users and make the users unnecessarily worry about the quality of the anesthetic, or even result in panic. In addition, because the O-shaped ring has a great process tolerance of design, which results in greater-insertion force during the insertion of the connecting valve structure into the evaporator, thus being inconvenient for medical staff to operate.